On May 30, 2009, at 9:02 AM, Greg Banks wrote:
On Sat, May 30, 2009 at 10:26 PM, Trond Myklebust
<trond.myklebust@xxxxxxxxxx> wrote:
On Sat, 2009-05-30 at 10:22 +1000, Greg Banks wrote:
On Sat, May 30, 2009 at 3:35 AM, Trond Myklebust
<trond.myklebust@xxxxxxxxxx> wrote:
On Fri, 2009-05-29 at 13:25 -0400, Brian R Cowan wrote:
Firstly, the server only uses O_SYNC if you turn off write gathering
(a.k.a. the 'wdelay' option). The default behaviour for the Linux nfs
server is to always try write gathering and hence no O_SYNC.
Well, write gathering is a total crock that AFAICS only helps
single-file writes on NFSv2. For today's workloads all it does is
provide a hotspot on the two global variables that track writes in an
attempt to gather them. Back when I worked on a server product,
no_wdelay was one of the standard options for new exports.
Really? Even for NFSv3/4 FILE_SYNC? I can understand that it
wouldn't have any real effect on UNSTABLE.
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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